Standard aerosol valve and gasket assemblies for dispensing pressurized product from a container have an inherent structural problem which limits the flow rate of product through the valve stem and out of the container. As is well known, the gasket which seals the conventional radial opening of the spring biased valve in the valve housing of conventional aerosol valves also seals the valve stem with the mounting cup of the container, limiting the diameter of the opening relative to the valve stem extending through the gasket. The valve stem is provided with both an axial and a radial opening for dispensing product from the container. When the valve stem is depressed inward or pushed down by a user against a spring bias, the radial opening, which is initially blocked by the gasket, is moved into fluid communication with the product contained in the container so that this product is then permitted to flow through the radial opening and out the valve stem and be discharged or dispensed into the environment. Once the user releases the valve stem, the valve stem is automatically returned back into its sealed, closed position with the mounting cup gasket again blocking the radial opening.
The structural problem is two-fold; first, the diameter of the radial opening formed in the sidewall of the valve stem must be smaller than the thickness of the gasket so that the radial opening is adequately covered and sealed in the closed valve position, otherwise there is a substantial risk of the product leaking or flowing into the radial opening and inadvertently able to escape the product contained even when the valve is closed. The thickness of a conventional gasket is typically in the range of 1.02 mm-1.52 mm (0.04-0.06 inches), so that the diameter of the radial opening must be substantially within this range or slightly smaller. This along with tolerances necessary to ensure complete closure of the valve limits the size of the radial opening. Secondly, the larger the radial opening formed in a side wall of an upper portion of the valve stem where it is typically located in such conventional valve stems, the greater the effect on the structural integrity of the valve stem. If the opening is too large, the valve stem, when subjected to axial and radial forces during depression by a user, can break, bend or otherwise permanently damage the valve stem or fail. Accordingly, it is difficult to obtain high flow rates of product due to such restrictions in the size of the radial opening in the stem. Further, highly viscous products, such as toothpaste and gels, cannot be dispensed without a sufficiently large passage being formed in the valve stem.
Similarly, in other applications such as bag-on-valve assemblies, such valve stem openings create the same or similar structural issues. Collapsible and highly flexible product bags or pouches have become common in different industries for containing a variety of food, beverages, personal care or household care or other similar products. Such product bags can be used alone to allow a user to manually squeeze and dispense a product from the bag or the product bag may be utilized in combination with a pressurized can and product, for example an aerosol. Such product bags and valves contained in and used with aerosol cans are generally referred to in the aerosol dispensing industry as bag-on-valve (BOV) technology. These product bags, valves and cans may be designed to receive and dispense a desired product in either a liquid or semi-liquid form which has a consistency so as to be able to be expelled from the valve or outlet by the user when desired.
Bag-on-valve technology is known to utilize a product dispenser, such as a can, which has an empty collapsible product bag inserted therein prior to filling of the bag with the desired product to be dispensed. The bag is initially flat and rolled up to form a smaller diameter so as to facilitate axial installation of the bag inside the can with a portion of a filling/dispensing valve communicating with an interior space of the product bag. During a final manufacturing phase, the product bag is filled with the desired product to be dispensed.
During the filling process, a desired product to be dispensed is inserted into the product bag via the two-way valve by conventional filling mechanisms. When the bag is filled by the filling mechanism, the product bag expands inside the can. At some point during the assembly process, the can is supplied with a pressurized gas, an aerosol or a compressed gas, in order to assist with squeezing the bag to expel the product contents thereof as is well known in the art. Many factors influence the expulsion of the contents or product to be dispensed from the can out of the valve into the environment. The valve is a key component, which led to the design of multiple valve configurations for a variety of different applications.
Typically, bag-on-valve applications use a valve that has two components, namely, a valve housing and a valve stem. For most applications, the valve housing engages with a mounting cup of a can, attaches to a bag that holds the product to be dispensed, and provides the framework for the valve stem. The valve stem usually interacts with the interior of the valve housing through the use of a spring. The spring allows the valve stem to move relative to the valve housing to open and close the valve. Typically, when the valve is opened, product to be dispensed flows from the product bag, to and through the valve housing, then through a passage in the valve stem, and finally the product is discharged, via a discharge nozzle of some sort, into the environment. The passage is normally limited in size and shape based on the sealing of the passage by the upper gasket that is used to seal the valve housing to the mounting cup.
One issue associated with the bag-on-valve technology is the control of the flow volume of the product contents from the bag for discharge into the environment. This issue is especially compounded due to the different viscosities of the various products which manufacturers desire to dispense from such bag-on-valve containers. The various product contents include, for example, liquids, creams, foams, gels, aerosols, colloids, and various other substances. Handling the flow of a highly viscous substance, such as toothpaste, is particularly difficult in both conventional and bag-on-valve applications where the aerosol dispensing radial openings or passages are particularly small, e.g., in the range of 1.02 mm-1.52 mm (0.04-0.06 in.) and there is no structural feasibility to make these radial openings or passages larger with conventional valve structures. The problem is to be able to accommodate larger dispensing openings in the valve greater than 1.02 mm-1.52 mm (0.04-0.06 in.) in order to accommodate more viscous product to be dispensed and at higher flow rates.
The present invention addresses the required increased flow rate necessary in some bag-on-valve applications. In some aerosol applications, however, the bag-on-valve containers may not be feasible due to volume constraints of the container and cost considerations, even though it may be undesirable to mix the propellant gas with the product material. In these instances, immiscible gases, such as nitrogen or carbon dioxide, may be preferred. The present invention provides for liquefied propellants or compressed gas, such as air, nitrogen or carbon dioxide, to be used and further may provide metered doses of product to be dispensed as required in some aerosol applications.